Cause and Effect

Farmers who may become the targets of the Province of Manitoba’s new regulations for the release of phosphorus into waterways have reason to be concerned. At best, these new rules will raise their costs. At worst, they could put some producers right out of business and prevent others from entering the market.

The rationale behind the new rules is algae blooms, especially Satellite photos that show a mass of blue-green blooms in the north basin of Lake Winnipeg. If such masses of algae get too big, they lead to oxygen depletion, with dire consequences for the entire eco-system. These blooms are the largest ever recorded in all of the North America’s large lakes.

Some evidence for depletion of biota has been discovered in the lake, but so far it is minimal. Record pickerel catches in Lake Winnipeg last summer indicate the opposite. It’s probably safe to say that the blooms are a potential problem, but no one knows where the tipping point is.

Experiments conducted on small lakes in northern Ontario have demonstrated the effect of phosphorus levels on the growth of these algae, which do occur naturally. Researchers hung a curtain across one of these lakes and on one side dumped in a combination of nitrogen and carbon and on the other side phosphorus. After time, the difference between the two sides became apparent. One side remained clear, while the other, where phosphorus was added, looked like it was covered with a green blanket. Additional research has shown it’s the phosphorus to nitrogen ratio, not the absolute level of phosphorous in the water, that’s responsible.

Once past satellite photos and the lake experiments, one quickly moves from hard science and into the murky grey of hypothesis. The biological and physical processes going on specifically in Lake Winnipeg have been the subjects of little research; it is the most poorly researched of lakes of its size. The few researchers who’ve looked at it admit that they really don’t know what makes it tick. They rely on studies from other areas, with different attributes, to draw conclusions.

The soil science is in a similar state of uncertainty. We have some understanding of what happens in Manitoba with the movement of phosphorus from soil into water, but again have to rely on outside data for conclusions and strategies for mitigation. Some remedies may work but, according to the soil scientists with the best credentials in this field, others may actually increase phosphorus transfers. Natural plant buffers in riparian areas—along the shores of stream, rivers and lakes—in some cases transfer more nutrients into water than straight crop land.

The Province of Manitoba maintains a network of 46 water-monitoring stations along various streams and rivers to measure the level of phosphorus they contain. But limitations in the methodology used, and the small number of samples taken every year over the last two decades, means that the reliability of the data is questionable. Conclusions based on this testing have also never been duplicated, a basic tenant of science. Since these stations will be counted upon to measure progress, they require a proper starting baseline, and assurances that the data is robust. There is little reason to believe that this is or can be the case.

Questions can also be raised about other numbers that don’t add up in various provincial reports, the selective use of data and the lack of information on urban point and non-point sources of phosphorus. Nor has the Province budgeted the money to improve the general lack of research in all these fields of study, or to expand its own miniscule regime of soil testing, both of which create a gaping hole in the links between cause and effect.

The province’s current goal is to reduce the amount of phosphorus going into Lake Winnipeg from all sources—more than half of which are outside its control—by 10%. This goal cannot be accurately measured and, by many accounts, even if it’s met may have zero effect on the algae blooms.

Farmers, especially those with small operations unable to bear the costs of compliance or even the paperwork burden needed to demonstrate compliance, may have to leave the land and those who want to buy existing operations or start news ones will think twice. What they have been doing for over a hundred years may not fit with the new regulations. They will find little solace in the Province’s inability to prove a direct cause and effect relationship back to their specific fields, or in blithe assurances that at least this is a precautionary step in the right direction. After they are gone, there’s a real chance the algae blooms will remain.